function stringToByte(str) {
    var bytes = new Array()
    var len, c
    len = str.length
    for (var i = 0; i < len; i++) {
        c = str.charCodeAt(i)
        if (c >= 0x010000 && c <= 0x10ffff) {
            bytes.push(((c >> 18) & 0x07) | 0xf0)
            bytes.push(((c >> 12) & 0x3f) | 0x80)
            bytes.push(((c >> 6) & 0x3f) | 0x80)
            bytes.push((c & 0x3f) | 0x80)
        } else if (c >= 0x000800 && c <= 0x00ffff) {
            bytes.push(((c >> 12) & 0x0f) | 0xe0)
            bytes.push(((c >> 6) & 0x3f) | 0x80)
            bytes.push((c & 0x3f) | 0x80)
        } else if (c >= 0x000080 && c <= 0x0007ff) {
            bytes.push(((c >> 6) & 0x1f) | 0xc0)
            bytes.push((c & 0x3f) | 0x80)
        } else {
            bytes.push(c & 0xff)
        }
    }
    return bytes
}

function byteToString(arr) {
    if (typeof arr === "string") {
        return arr
    }
    var str = "",
        _arr = arr
    for (var i = 0; i < _arr.length; i++) {
        var one = _arr[i].toString(2),
            v = one.match(/^1+?(?=0)/)
        if (v && one.length == 8) {
            var bytesLength = v[0].length
            var store = _arr[i].toString(2).slice(7 - bytesLength)
            for (var st = 1; st < bytesLength; st++) {
                store += _arr[st + i].toString(2).slice(2)
            }
            str += String.fromCharCode(parseInt(store, 2))
            i += bytesLength - 1
        } else {
            str += String.fromCharCode(_arr[i])
        }
    }
    return str
}
module.exports = { byteToString, stringToByte }
